Weld said despite President Trump’s popularity within the party — Trump has an 89 percent approval rating, according to the latest Gallup poll — he felt a duty to try to unseat him.

“I really think if we have six more years of the same stuff we’ve had out the White House the last two years, that would be a political tragedy and I would fear for the republic,” Weld said. “So I would be ashamed of myself if I didn’t raise my hand and run.”

Former Massachusetts Gov. William Weld having a coffee in New Hampshire. He's said he and Donald Trump "have nothing in common, other than being large, orange men."

Credit Anthony Brooks / WBUR

Weld said his career as a federal prosecutor stands in stark contrast to the president.

“I spent seven years the Justice Department trying to keep the politics out of law enforcement,” Weld said of his work as a U.S. attorney and head of the Justice Department’s criminal division. “He’s trying to put it in.”

“He has difficulty confirming his conduct to the requirements of law, that's a serious matter in the Oval Office,” Weld added.

Weld left the Republican Party to become the Libertarian vice presidential nominee in 2016. He returned to the GOP in February, and soon after announced he was considering a challenge to Trump.

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